The transition of breast cancer treatment and Japan Clinical Oncology Group research over two decades.

The Japanese Breast Cancer Study Group (JABCSG) was established before the Japan Clinical Oncology Group (JCOG). The JABCSG became the JCOG Breast Cancer Group 20 years ago. The first chairman of the Breast Cancer Group was Dr Kaoru Abe (National Cancer Center Hospital). Since 1978, five doctors have chaired the Breast Cancer Group. Sixteen clinical trials (eight phase III and eight phase I/II) have been conducted by the Breast Cancer Group since 1985. The Breast Cancer Group was restructured in 2010, and in June 2011 a new clinical trial (JCOG 1017) was initiated. Standard treatment for breast cancer (surgery, radiotherapy and systemic therapy) has changed dramatically over the last two decades. This review describes the transition of breast cancer treatment along with the history of JCOG research in this setting.